This invention relates to preparation of an essentially oligomer free (hereinafter simply "oligomer free") 1,1,1-trifluoro-3-chloro-2-propene (1233zd) by the uncatalyzed liquid phase fluorination of 1,1,3,3-tetrachloro-2-propene (1230za), particularly to such processes wherein said 1230za is contacted with a large molar excess of hydrogen fluoride (for convenience hereafter referred to as "HF"). The 1233zd product is a known intermediate for producing 245fa, as taught, for example, in U.S. Pat. No. 5,616,819 and in copending application 08/980,747, filed Dec. 1, 1997.
U.S. Pat. No. 5,616,819 discloses that previous attempts to fluorinate 1230za to 1233zd in an uncatalyzed liquid phase reaction resulted in the formation of a substantial amount of oligomeric products (19 g of oligomeric material in Example 1.i., the result of using a 6:1 molar ratio of the HF and 1230za starting materials). It is thus an object of this invention to provide an uncatalyzed liquid phase fluorination process for successfully converting 1230za to oligomer free 1233zd.